The Cynical Helix Ploy exploits the fact that helixes score well in Foldit.
The ploy involves turning the entire protein into one or more helixes, and applying the idealize secondary structure tool to make perfect spirals. Cutpoints and the move tool can be used to align the helixes in so they're parallel in space.
The ploy can be used to achieve a good score on some beginner puzzles.
With a little effort, a similar strategy can also be applied to some de-novo puzzles. In a de-novo, the prolines and glycines tend to indicate turns or bends in the backbone. Prolines and glycines aren't usually found in the middle of helixes and sheets. Keeping this in mind, and paying attention to which way the hydrophobic segments point, it may be possible to create a mostly-helix solution which scores reasonably well on at least some de-novo puzzles.
Most recent Foldit design puzzles have limited helixes to 50% of the segments. In these puzzles, a condition applies a substantial penalty if too many segments are in a helix. This approach foils the Cynical Helix Ploy, but most players still design proteins with the maximum number of segments in helixes.